Ulnar Defect Research Articles

Establishing rabbit critical-size bone defects to evaluate the bone-regeneration potential of porous calcium phosphate ceramics

Critical-size bone defects (CSDs), which are those that do not self-repair in a given period, are essential for evaluating bone-regeneration strategies. We established CSDs models in the rabbit cranium and ulna, and the bone-regeneration capacities of porous calcium phosphate (CaP) ceramics were assessed. A 12.6-mm cranial defect was confirmed as a CSDs after 12 weeks, with submicron surface-structured biphasic calcium-phosphate (BCP) implants [consisting of 20% hydroxyapatite and 80% tricalcium phosphate (TCP)] demonstrating significantly higher bone formation (32.2% ± 10.6%) than micron surface-structured TCP (TCP-B) implants (17.8% ± 4.6%, p = 0.0121). Ulna defects (15.0 mm in length) failed to heal spontaneously within 24 weeks when the periosteum was removed from both the ulna and radius, and the radius was covered with an expanded polytetrafluoroethylene (ePTFE) membrane. No bone bridging (i.e., union) was observed in the BCP implants at 12 weeks, whereas 80% of BCP implants (four out of five) achieved union by 24 weeks. Furthermore, the bone area within the available space of BCP implants increased significantly from 19.3% ± 7.3% at 12 weeks to 37.7% ± 8.5% at 24 weeks (p = 0.0063), accompanied by significant BCP resorption (14.8% at 12 weeks and 30.2% at 24 weeks). This study offers two rabbit CSDs models for evaluating bone-regeneration strategies (including bone substitution), and the overall data obtained in the current study indicate the possibility of repairing CSDs with CaP ceramics demonstrating improved bone-forming ability given adequate implantation time.

Regeneration of a Rabbit Segmental Defect with a New Bone Therapy: Autologous Blood Coagulum with Bone Morphogenetic Protein 6 and Synthetic Ceramics

Segmental defects of long bones are among the most challenging and debilitating conditions in clinical medicine. Osteogrow-C is a novel osteoinductive device composed of recombinant human bone morphogenetic protein 6 (rhBMP6) delivered within autologous blood coagulum (ABC) with calcium phosphate ceramics that was proven efficacious in preclinical models of spinal fusion. This study aimed to evaluate the efficacy of Osteogrow-C in comparison to that of other osteoinductive therapies in a clinically relevant segmental defect model in rabbits. Segmental defects (15 mm) of rabbit ulna were treated with Osteogrow-C containing different synthetic ceramic particles (tricalcium phosphate [TCP] and TCP/hydroxyapatite 40%/60%), Osteogrow (rhBMP6/ABC), Infuse (rhBMP2/absorbable collagen sponge), and control implants without bone morphogenetic proteins. Defect healing was evaluated by in vivo x-ray scans 4, 8, and 17 weeks after the surgery, and animals were killed after 17 weeks for further radiographical and histological assessment. Evaluation of x-ray images, micro-computed tomography, and histological sections revealed that both Osteogrow-C formulations as well as Osteogrow and Infuse promoted healing of the ulnar segmental defect. However, radiographic scores were higher in animals treated with Osteogrow-C than those for the other used therapies. Moreover, evaluation of in vivo x-ray scans revealed that Osteogrow-C with TCP ceramics induced the most rapid defect bridging. On the other hand, control implants (ABC/TCP and ABC/biphasic calcium phosphate) promoted limited osteogenesis without defect bridging. The findings of this study suggest that Osteogrow-C is a promising safe therapeutic solution for the treatment of large bone defects, providing relief to millions of patients suffering from this debilitating condition.

Bacteriophage Therapy for Acute Fracture-Related Infections: An Effective Treatment When Compared to Antibiotics In A Canine Model.

Acute fracture-related infections are challenging problems, affecting up to 20% of orthopaedic trauma patients. High recurrence rates, secondary surgeries, and rehospitalizations lead to increased healthcare costs and are major burdens to patients. Bacteriophage therapy offers a potential alternative treatment option to address these challenges. In previous studies, it has been shown to be effective against biofilm and bacterial clearance on orthopaedic implants, however, their effects on fracture healing are poorly understood. The aim of this study was to determine if bacteriophages are as good as antibiotic therapy for the treatment of fracture related infection. A canine model was used for this preclinical study examining bacteriophages specifically cultivated against S. aureus (OJ1). Based on sample size calculations and ethical care and use of animals, bilateral 1 cm ulnar defects (n=32; 16 dogs) were created and stabilized using plate and screw fixation. Implants were incubated in a suspension of biofilm-producing Staphylococcus aureus (OJ1). After 3 weeks, bone samples from fracture sites were cultured and surgical sites underwent irrigation and debridement (I&D) with retention of hardware, followed by 1 of 4 treatments (n=8/group): no additional treatment, 6 weeks of parenteral antibiotics, 7 days of bacteriophage therapy, or combination antibiotic/bacteriophage therapy. At 11 weeks, dogs were humanely euthanatized and bacterial load, callus formation, and histomorphometry for callus maturity and biofilm formation were assessed using quantitative microbial bone cultures, radiography and semi-quantitative histomorphometry. At 3 weeks, all surgical sites/ulnae had confirmed infections . At 11 weeks, fractures that received bacteriophage therapy (542 ± 204 CFU/g) had statistically significantly less CFU/g when compared to those (45,065 ± 4,409 CFU/g) that did not receive bacteriophage (p=0.033). Fractures treated with bacteriophages had statistically significantly (p<0.0001) more robust callus formation on radiographs at 11 weeks (77.7% ± 9% vs 52.5% ± 14%), as well as decreased biofilm formation (median = 1 vs 2; p=0.049) and statistically significant (p=0.035) increase in bone formation on histology/histomorphometry when compared to fractures that did not receive bacteriophages (20.7 ± 6 vs 15.7 ± 7). Seven days of bacteriophage therapy was at least as good as 6 weeks of antibiotic therapy in terms of clearance of acute fracture-related infections. It was superior in terms of reduction in CFU/g, better callus formation, and biofilm clearance.

The use of a vascularized fibular flap in the treatment and surgical rehabilitation of military trauma patients

Aim. The purpose of the work is to demonstrate the possibilities of using a vascularized fibular flap to replace bone defects in the treatment of acute military trauma and its consequences at the rehabilitation stage. Materials and methods. An anatomical feature description of the vascularized fibular flap with a cutaneous component. Clinical cases of the vascularized fibular flap use to reconstruct bone and soft tissue defects after military injuries. In the presented cases, vascularized fibula osteocutaneous flaps were used. Results. Two clinical cases of reconstruction using the fibula flap are presented. The first case presents a patient with a total mandibular defect resulting from a gunshot wound. The second case presents a patient with consequences of a mine-shrapnel injury of the left forearm and an ulnar defect of about 12 cm in length and the resultant inability to perform rotational movements. Vascularized fibula osteocutaneous flaps were used for reconstruction in both cases being transferred to the recipient site, and microvascular anastomoses were performed for flap reperfusion. Conclusions. Adding a free fibula flap to the reconstructive surgeon’s arsenal enables one-stage reconstructions of large wounds with bone defects after injuries or oncological resections without significant musculoskeletal functional loss to donor limbs.

Outcomes of Free Vascularized Fibular Grafts in Treating Massive Forearm Skeletal Defects.

Reconstructing long bone defects in the upper limbs, particularly the radius and ulna, poses significant challenges. These defects, resulting from trauma, tumors, infections, or congenital anomalies, require precise surgical intervention for functional restoration. Traditional non-vascularized autogenous bone grafts have limitations, such as resorption and limited biological activity. To address these challenges, free vascularized fibular grafts (FVFGs) have been developed, offering enhanced recovery by supplying nutrients and structural support, particularly in large defects or compromised vascularity. This retrospective study reviewed patients with significant forearm skeletal defects treated with FVFGs at our institution from January 2008 to January 2019. Included were patients with radius or ulna defects exceeding 8 cm due to trauma, tumor excision, or non-union fractures. Data on demographics, clinical details, surgical techniques, and outcomes-including graft union time, complications, range of motion, and the disabilities of the arm, shoulder and hand (DASH) scores-were analyzed. Eight patients, with a mean age of 27.6 years and an average defect length of 9.8 cm, were included. All patients achieved graft union within an average of 4 months, with no tumor recurrence or significant complications. Functional outcomes showed mean forearm pronation of 56.9 degrees, supination of 52.5 degrees, and a mean DASH score of 17.7. FVFG is a safe and effective technique for managing complex forearm bone defects, providing high union rates and good functional outcomes. It should be considered a primary option for large forearm skeletal defects.

Direct Suturing of Ulnar or Median Nerve Defects in High-Degree Elbow Flexion: An Experimental Cadaver Study

The aim of this study is to determine the maximum loss of median and ulnar nerve substances that can be treated by direct suture in elbow flexion and to quantify this elbow flexion. The other objective is to determine the participation of the wrist position in this direct suture in elbow flexion. We performed an experimental study on 6 ulnar nerve lesions and 6 median nerve lesions. For each defect, a direct tensionless suture was performed with elbow flexion and in three different positions of the wrist (wrist extension, neutral position, and wrist flexion). A 90° elbow flexion allowed direct suturing of defects up to 40 mm in the 3 positions of the wrist. A bowstringing effect (i.e., increase of the perpendicular distance of the nerve from the axis of rotation of the elbow) was noted starting from 25 mm of nerve defect. Wrist extension placed tension on the nerve suture for both nerves. The results of this first anatomical study clarified the conditions for direct suturing of ulnar and median nerve defects in the flexed elbow position and flexed wrist position. This is an approach to consider for limited nerve defects to the elbow or when allograft harvesting is to be avoided.

Comparison of reamer irrigator aspirator (RIA) suspension versus bone marrow aspirate concentrate (BMC) for percutaneous treatment of long bone nonunions—A preclinical canine model

ObjectiveTo compare the bone healing effects of percutaneously delivered bone marrow aspirate concentrate (BMC) versus reamer irrigator aspirator (RIA) suspension in a validated preclinical canine ulnar nonunion model. We hypothesized that BMC would be superior to RIA in inducing bone formation across a nonunion site after percutaneous application. The null hypothesis was that BMC and RIA would be equivalent. MethodsA bilateral ulnar nonunion model (n= 6; 3 matched pairs) was created. Eight weeks after segmental ulnar ostectomy, RIA from the ipsilateral femur and BMC from the proximal humerus were harvested and percutaneously administered into either the left or right ulnar defect. The same volume (3 ml) of RIA suspension and BMC were applied on each side. Eight weeks after treatment, the dogs were euthanized, and the nonunions were evaluated using radiographic, biomechanical, and histologic assessments. ResultsAll dogs survived for the intended study duration, formed radiographic nonunions 8 weeks after segmental ulnar ostectomy, and underwent the assigned percutaneous treatment. Radiographic and macroscopic assessments of bone healing at the defect sites revealed superior bridging-callous formation in BMC-treated nonunions. Histologic analyses revealed greater amount of bony bridging and callous formation in the BMC group. Biomechanical testing of the treated nonunions did not reveal any significant differences. ConclusionBone marrow aspirate concentrate (BMC) had important advantages over Reamer Irrigator Aspirator (RIA) suspension for percutaneous augmentation of bone healing in a validated preclinical canine ulnar nonunion model based on clinically relevant radiographic and histologic measures of bone formation.

Axonal mapping of motor and sensory components within the ulnar nerve and its branches.

Intrinsic function is indispensable for dexterous hand movements. Distal ulnar nerve defects can result in intrinsic muscle dysfunction and sensory deficits. Although the ulnar nerve's fascicular anatomy has been extensively studied, quantitative and topographic data on motor axons traveling within this nerve remain elusive. The ulnar nerves of 14 heart-beating organ donors were evaluated. The motor branches to the flexor carpi ulnaris (FCU) and flexor digitorum profundus (FDP) muscles and the dorsal branch (DoBUN) as well as 3 segments of the ulnar nerve were harvested in 2-cm increments. Samples were subjected to double immunofluorescence staining using antibodies against choline acetyltransferase and neurofilament. Samples revealed more than 25,000 axons in the ulnar nerve at the forearm level, with a motor axon proportion of only 5%. The superficial and DoBUN showed high axon numbers of more than 21,000 and 9300, respectively. The axonal mapping of more than 1300 motor axons revealed an increasing motor/sensory ratio from the proximal ulnar nerve (1:20) to the deep branch of the ulnar nerve (1:7). The motor branches (FDP and FCU) showed that sensory axons outnumber motor axons by a ratio of 10:1. Knowledge of the detailed axonal architecture of the motor and sensory components of the human ulnar nerve is of the utmost importance for surgeons considering fascicular grafting or nerve transfer surgery. The low number of efferent axons in motor branches of the ulnar nerve and their distinct topographical distribution along the distal course of the nerve is indispensable information for modern nerve surgery.

Bioactive Bone Substitute in a Rabbit Ulna Model: Preclinical Study.

Current therapies to effectively treat long-bone defects and extensive bone tissue loss remains limited. In this study, we created a new bone substitute by integrating advanced technologies such as structure patterning, controlled release of a bone growth factor and conjugation system for clinically effective bone regeneration. This novel bioactive bone substitute was evaluated for its safety and efficacy using a rabbit ulna model. A three dimensional bone patterned cylindrical structure with 1.5cm in length and 5mm in diameter was printed using poly(L-lactic acid)(PLLA) as a weight-bearing support and space-filling scaffold. And a bone morphogenetic protein 2 (BMP2) was employed to enhance bone regeneration, and coated to a 3D PLLA using alginate catechol and collagen to prolong the release kinetics. This novel bone substitute (BS)was evaluated for its physico-chemical and biological properties in vitro, and histological analysis and radiographical analysis such as X-ray, CT and micro-CT image analysis were performed to evaluate new bone formation in vivo. The BS possesses an ideal shape and mechanically suitable proeperties for clinical use, with an easy-to-grab and break-resistant design at both ends, 80 ± 10MPa of compression strength, and BMP2 release for two months. Histological analysis demonstrated the biocompability of BS with minimal inflammation and immune response, and X-ray, CT and micro-CT demonstrated effective new bone formation in rabbit ulna defect model. The preclinical study of a novel bioactive bone substitute has shown its safe and effective properties in an animal model suggesting its clinical potential.

Outcomes of radiocarpal pinning to facilitate nerve repair in wrist level ulnar nerve injuries with defect.

The ideal scenario for ulnar nerve repair is primary end-to-end neurorrhaphy in a tension-free environment. However, this could be complicated by soft tissue loss, scarring and neuroma formation in a delayed injury, creating a nerve defect. With a wrist level nerve defect, a flexion position can help shorten the nerve gap. However, maintaining the position can be challenging intraoperatively and postoperatively. We proposed our method previously of using a 1.6mm K wire for radio-lunate-capitate pinning of the wrist in flexion to minimize the nerve gap, thereby facilitating neuroma excision and end-to-end neurorrhaphy in delayed ulnar nerve injury. In this study, we elaborate our method and present our case series. From October 2018 to July 2020, 5 patients (mean age: 48.2 years; mean delay from injury to surgery: 84.6 days; mean follow-up: 17.5 months) were retrospectively reviewed. The mean flexion fixation angle was 52 degrees and the K wire was removed at an average of 5.1 weeks postoperatively. All patients were followed-up for a minimum of 12 months. All patients achieved M4 and S3 or S3+ neurologically (according to the criteria of the Nerve Injuries Committee of the British Medical Research Council). The mean Disabilities Arm Hand and Shoulder score was 14.1. The mean grasp and pinch strengths were, respectively, 76.8% and 63.6% of the contralateral hand. All wrist range-of-motion returned to normal within 12 weeks. No complications were noted intraoperatively or postoperatively. Our study showed that radiocarpal pinning of the wrist in flexion was safe and convenient to minimize the nerve gap and to facilitate end-to-end neurorrhaphy in limited-sized wrist-level ulnar nerve defects.

Cell-free and cytokine-free self-assembling peptide hydrogel-polycaprolactone composite scaffolds for segmental bone defects.

Segmental bone defects over the self-healing threshold are a major challenge for orthopedics. Despite the advancements in clinical practice, traditional tissue engineering methods are limited by the addition of heterogeneous cells and cytokines, leading to carcinoma or other adverse effects. Here, we present a cell-free and cytokine-free strategy using an ECM-mimetic self-assembling peptide hydrogel (SAPH)- polycaprolactone (PCL) composite scaffold. The hydrophilic SAPH endows the rigid PCL scaffold with excellent biocompatibility and preference for osteogenesis induction. The autologous cells around the bone defect site immediately grew, proliferated, and secreted ECM and cytokines after contacting the implanted SAPH-PCL composite scaffold, and the bone repair of rabbit ulnar segmental bone defect was achieved in just six months. Quantitative proteomic analysis reveals that the SAPH-PCL composite scaffold accelerates osteoblastogenesis, osteoclastogenesis, and angiogenesis with moderate immune responses and negligible effects on pathological fibrosis. These findings have important implications for the potential clinical applications of the SAPH-PCL composite scaffold in patients with segmental bone defects and identify the mechanisms of action for accelerated segmental bone defect repair.

Histopathological and radiographical evaluation of caprine demineralized bone matrix in a critical ulnar defect in a rabbit model

BackgroundCaprine species satisfy the conditions of an ideal donor animal when compared to bovine species that has been extensively studied and commercialized for bone xenograft. Histopathological and radiological evaluations of caprine demineralized bone matrix (CDBM) were therefore carried out for fracture healing properties for its possible use in bone grafting procedures.Materials and methodsTwenty-four rabbits were used for this study and were divided randomly into three groups of eight (n = 8) rabbits each. Critical bone defect was created on the ulnar diaphysis under xylazine-ketamine anaesthesia for autogenous bone graft (ABG) group, CDBM group and the last group was left unfilled as negative control (NC). Immediate post-grafting radiograph was taken and repeated on days 14, 28, 42 and 56 to monitor the evidence of radiographic healing. The animals were euthanized on day 56 and defect sites were harvested for histopathology.ResultsThere was a progressive evidence of radiographic healing and bone formation in all the groups with significance difference (P = 0.0064). When compared with ABG, NC differ significantly (P < 0.0001) whereas the CDBM did not differ significantly (P = 0.6765). The histopathology sections of ABG and CDBM showed normal bone tissue while the NC section was predominated by fibrous connective tissue. There was therefore an overall significant difference (P = 0.0001) in which CDBM did not differ from ABG (P = 0.2946) while NC did (P = 0.0005).ConclusionThe ABG and CDBM groups showed a similar healing effect in the critical bone defect. Therefore, CDBM could be used as an effective alternative to ABG in orthopaedics to circumvent the limitations and complications associated with it.Level of evidenceNot applicable.

Recombinant human bone morphogenetic protein 2/porous calcium phosphate cement/autologous bone and combination of platelet-rich plasma in repairing of large bone defects in rabbits by Masquelet technique

To investigate the optimal mixing ratio of recombinant human bone morphogenetic protein 2 (rhBMP-2) with porous calcium phosphate cement (PCPC) and autologous bone as bone grafting material for the repair of large bone defects using Masquelet technique. The effect of platelet-rich plasma (PRP) on the healing of bone defects was evaluated under the optimal ratio of mixed bone. Fifty-four New Zealand White rabbits were taken to establish a 2 cm long bone defect model of the ulna and treated using the Masquelet technique. Two parts of the experiment were performed in the second phase of the Masquelet technique. First, 36 modeled experimental animals were randomly divided into 4 groups ( n=9) according to the mass ratio of autologous bone and rhBMP-2/PCPC. Group A: autologous bone (100%); group B: 25% autologous bone+75% rhBMP-2/PCPC; group C: 50% autologous bone+50% rhBMP-2/PCPC; group D: 75% autologous bone+25% rhBMP-2/PCPC. The animals were executed at 4, 8, and 12 weeks postoperatively for general observation, imaging observation, histological observation (HE staining), alkaline phosphatase (ALP) activity assay, and biomechanical assay (three-point bending test) were performed to assess the osteogenic ability and to determine the optimal mixing ratio. Then, 18 modeled experimental animals were randomly divided into 2 groups ( n=9). The control group was implanted with the optimal mixture ratio of autologous bone+rhBMP-2/PCPC, and the experimental group was implanted with the optimal mixture ratio of autologous bone+rhBMP-2/PCPC+autologous PRP. The same method was used to observe the above indexes at 4, 8, and 12 weeks postoperatively. The bone healing process from callus formation to the cortical connection at the defected gap could be observed in each group after operation; new bone formation, bridging with the host bone, and bone remodeling to normal bone density were observed on imaging observation; new woven bone, new capillaries, bone marrow cavity, and other structures were observed on histological observation. The ALP activity of each group gradually increased with time ( P<0.05); the ALP activity of group A was significantly higher than that of the other 3 groups at each time point after operation, and of groups C and D than group B ( P<0.05); there was no significant difference between groups C and D ( P>0.05). Biomechanical assay showed that the maximum load in three-point bending test of each group increased gradually with time ( P<0.05), and the maximum loads of groups A and D were significantly higher than that of groups B and C at each time point after operation ( P<0.05), but there was no significant difference between groups A and D ( P>0.05). According to the above tests, the optimal mixing ratio was 75% autogenous bone+25% rhBMP-2/PCPC. The process of new bone formation in the experimental group and the control group was observed by gross observation, imaging examination, and histological observation, and the ability of bone formation in the experimental group was better than that in the control group. The ALP activity and maximum load increased gradually with time in both groups ( P<0.05); the ALP activity and maximum load in the experimental group were significantly higher than those in the control group at each time point after operation ( P<0.05), and the maximum load in the experimental group was also significantly higher than that in group A at 12 weeks after operation ( P<0.05). In the second phase of Masquelet technique, rhBMP-2/PCPC mixed with autologous bone to fill the bone defect can treat large bone defect of rabbit ulna, and it has the best osteogenic ability when the mixing ratio is 75% autologous bone+25% rhBMP-2/PCPC. The combination of PRP can improve the osteogenic ability of rhBMP-2/PCPC and autologous bone mixture.

Keystone flap for reconstruction of ulnar side defect of the hand: a case report

Soft tissue defects of the hand may present in various forms and are often challenging to treat. The goal of surgical hand reconstruction includes both functional and aesthetic aspects. The keystone-design perforator island flap is a multi-perforator advancement flap with a safe flap harvesting technique, reliable blood supply, minimal donor site morbidity, and a simple dissection process that obviates the need for microsurgical techniques. Our patient was an 85-year-old man with squamous cell carcinoma on the left-hand ulnar side. The patient had difficulty in ambulation and used the affected area of the hand to stand up. Thus, we planned reconstruction using an omega-variant type B keystone flap to further reduce tension during flap insetting and to provide sufficient padding that would protect against excessive pressure postoperatively. The flap and donor site were closed primarily, without any postoperative complications. The patient was satisfied with the outcome after 19-month follow-up.

Outcome Analysis of Osseous Ingrowth in an Artificially Created Gap Non-union Using the Novel 3D Biodegradable Polycaprolactone Poly-l-Lactide Polymer Scaffold: Insights from an Experimental Study.

Synthetic biopolymers have been widely used to manage bone effects in recent years. The study aims to analyse the ability to repair artificially created ulnar bone defects with the scaffold made of Polycaprolactone (PCL) and investigate the material's feasibility as a bone graft substitute. We have tested a novel 3D biodegradable Polycaprolactone Poly-l-Lactide polymer scaffold in an experimental animal model. 14 adults New Zealand white rabbits were used to create the ulnar defect model of 10mm in length, and randomly divided into group A (test-12 rabbits), group B (control-3 rabbits). The defect area was implanted with the PCL scaffold in the test group, whereas it was left as such in the control group. The repairing effect was observed by gross, histology, radiology, and the Scanning electron microscopy (SEM) at 4, 8, and 12weeks. Cook's scoring was used to assess the radiological parameters. Histological and radiological results showed better quality of bone regeneration in the defect area at 12week follow-up period. The SEM image at that period showed impregnation of the osteogenic cells in the surface and pores of the scaffold material. It was evident that the scaffold was thoroughly degraded, corresponding with osteogenesis. New bone formation was statistically significant in the test group than in the control group. The Polycaprolactone Poly-l-Lactide polymer scaffold is biodegradable in-vivo at a suitable half-life. It has an excellent porous structure, no tissue toxicity, excellent mechanical strength, high osteogenesis potential, and osteoconductivity. Therefore, it can be used as bone graft material in the gap non-union and as a void filler in bone defects.

Treatment of upper extremity nerve defects by direct suturing in high elbow or wrist flexion.

To evaluate functional outcomes after direct suturing of upper extremity nerve defects in high elbow or wrist flexion. A retrospective review was conducted in patients treated for median, ulnar, or radial nerve defects between 2011 and 2019. Inclusion criteria were a defect > 1cm and a minimal follow-up period of 1year. Nerve defects were bridged by an end-to-end suture in 90° elbow flexion or 70° wrist flexion for 6weeks. Nine patients with a mean age of 30.2years were included. The patients presented with two ulnar nerve defects, four median nerve defects, and three radial nerve defects at various levels. The mean time to surgery was 13.5weeks for recent injuries. The mean defect length was 2.9cm, and the mean follow-up time was 22.4months. Two patients had joint stiffness that was more likely related to the associated injuries than the 6-week immobilization. Successful outcomes were achieved in eight of the nine patients. Meaningful motor recovery was observed in seven patients, and all recovered meaningful sensation. Excellent nerve recovery was noted in pediatric patients and in those with distal nerve defects. Temporary high joint flexion allows for direct coaptation of upper extremity nerve defects up to 4cm located near the elbow or wrist. In this small and heterogenous cohort, functional outcomes seemed to be comparable to those obtained with short autografting.

Does zinc oxide nanoparticles potentiate the regenerative effect of platelet-rich fibrin in healing of critical bone defect in rabbits?

BackgroundMany encouraging studies confirmed the ability of Zinc Oxide Nanoparticles (ZnONPs) in accelerating bone growth and mineralization. The use of Platelet Rich-Fibrin (PRF) as a sole filling material for large segmental bone defects remains questionable. The objectives are to investigate the regenerative efficacy of autologous Platelet Rich-Fibrin (PRF) and Zinc Oxide Nanoparticles (ZnONPs) in repairing large segmental bone ulnar defects in a randomized controlled study in rabbits using computed tomographic interpretations. A 12 mm critical size defect was surgically induced in the ulna of 30 rabbits (n = 10/ group). In the control group, the defect was left empty. In the PRF group, the defect is filled with PRF. In the PRF/ZnONPs group, the defect is filled with PRF that was inoculated with 0.1 ml of 0.2% ZnONPs. Radiologic healing capacity was evaluated at the first, second, and third postoperative months.ResultsStatistical analysis showed significant differences in the radiologic healing scores between the groups (P = 0.000–0.0001) at all-time points (P = 0.000–0.047) during the study.ConclusionRabbits in the PRF/ZnONPs group showed the highest appreciable bone quality and quantity followed by the PRF group with high quantity but low bone quality meanwhile, rabbits in the control group showed minimal quantity but medium bone quality. Interestingly, the addition of ZnONPs to PRF can accelerate the healing of ulnar critical-size defects in rabbits.

Nanohydroxyapatite-Protein Interface in Composite Sintered Scaffold Influences Bone Regeneration in Rabbit Ulnar Segmental Defect

The healing physiology of bone repair and remodeling that occurs after normal fracture is well orchestrated. However, it fails in complex clinical conditions and hence requires augmentation by grafts. In this study, composite nanohydroxyapatite (nHA), poly(hydroxybutyrate) (PHB) and poly(ɛ-caprolactone) (PCL) constituted microspheres sintered three-dimensional scaffold were evaluated in rabbit ulnar segmental defect. A composite scaffold using PHB-PCL-nHA microspheres was developed with protein interface by solvent/non-solvent sintering to provide multiple cues such as biocomposition, cancellous bone equivalent meso-micro multi-scale porosity, and compressive strength. In vitro DNA quantification and alkaline phosphatase (ALP) assays revealed that the protein interfaced composite scaffolds supported osteoblast proliferation and mineralization significantly higher than scaffolds without protein and TCPS (p < 0.05). Scanning electron micrographs of osteoblasts cultured scaffolds demonstrated cell-matrix interaction, cell spreading, colonization and filopodial extension across the porous voids. Cylindrical scaffolds (5 × 10 mm) were implanted following segmental defect (10 mm) in rabbit ulnar bone and compared with untreated control. Radiography (4, 8 and 12 weeks) and µ-computed tomography (12 weeks) analysis showed directional bone tissue formation by bridging defective site in both scaffolds with and without protein interface. Whereas, undesired sclerotic-like tissue formation was observed in control groups from 8 weeks. Histology by hot Stevenel’s blue and van Gieson’s picrofuchsin staining has confirmed enhanced bone maturation in scaffold groups while presence of osteoids was observed in control after 12 weeks. Thus, the developed composite matrices exhibits osteoinductive, osteoconductive properties and demonstrates its bone regenerative potential owing to its compositional, micro & macro structural and mechanical properties.Graphical abstract

A unique salvage operation strategy: implantation of the ulnar total elbow component to the radius to overcome large ulnar bone defect caused by infection after total elbow arthroplasty.

The elbow joints of patients with rheumatoid arthritis (RA) are often destroyed, and total elbow arthroplasty (TEA) is one treatment for these patients. However, patients with RA tend to develop surgical site infections due to immunosuppression. Once an implant is infected, reoperation may be difficult because of the risk of reinfection. In such patients, the infected site must be debrided thoroughly, although this might reduce the bone scaffold needed for re-TEA. We used a unique method to manage a large ulnar bone defect and an infected implant. The patient with RA had undergone TEA 15 years earlier. Etanercept was initiated to control disease activity; however, this treatment led to infection of the elbow prosthesis. Several surgical debridements were performed to eradicate the bacteria, which improved the symptoms of infection. However, most of the proximal ulna was lost, and it seemed impossible to fix the prosthesis using the remaining small ulna after debridement. Therefore, we planned to implant the ulnar component into the radius as a salvage technique. With this procedure, we provided the patient with elbow mobility and eradicated the infection. This is an alternative method for restoring function in an elbow with a massive bone defect in the ulna.

A Double-Barreled Fibular Graft for the Reconstruction of Both Forearm Bones and Humeroradial Joint after a Tumor Resection.

A double-barreled fibular graft was used to reconstruct both forearm bones and the humeroradial joint after tumor resection. The patient had a tumor of radius that invaded the ulna and extensor groups. After a wide tumor resection, vascularized fibular autograft and soft tissue reconstruction was performed. A fibular graft were placed as a double barrel in the proximal ulnar and radial defects including the radial head and fixed using two locking plates. Simultaneously, reconstruction of the humeroradial joint and wrist dorsiflexion was performed. Two years postoperatively, the patient is satisfied with his elbow function while performing activities of daily living. Although amputation was one of the options considered during the preoperative planning in this case, the affected limb could be preserved by grafting a double-barreled fibula and tendon transfer, which could maintain the function of his upper left limb.